package cn.bluemobi.dylan.step.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.TabHost;
import android.widget.TabWidget;

import java.util.ArrayList;

/** 
 * Special TabHost that allows the use of {@link Fragment} objects for its tab 
 * content. When placing this in a view hierarchy, after inflating the hierarchy 
 * you must call {@link #setup(Context, FragmentManager, int)} to complete the
 * initialization of the tab host. 
 *  
 * <p> 
 * Here is a simple example of using a FragmentTabHost in an Activity: 
 *  
 * {@sample 
 * development/samples/Support4Demos/src/com/example/android/supportv4/app/ 
 * FragmentTabs.java complete} 
 *  
 * <p> 
 * This can also be used inside of a fragment through fragment nesting: 
 *  
 * {@sample 
 * development/samples/Support4Demos/src/com/example/android/supportv4/app/ 
 * FragmentTabsFragmentSupport.java complete} 
 */  
public class MyFragmentTabHost extends TabHost implements
        TabHost.OnTabChangeListener {
    private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
    private FrameLayout mRealTabContent;
    private Context mContext;
    private FragmentManager mFragmentManager;  
    private int mContainerId;  
    private OnTabChangeListener mOnTabChangeListener;
    private TabInfo mLastTab;
    private boolean mAttached;

    static final class TabInfo {
        private final String tag;
        private final Class<?> clss;
        private final Bundle args;
        private Fragment fragment;

        TabInfo(String _tag, Class<?> _class, Bundle _args) {
            tag = _tag;
            clss = _class;
            args = _args;
        }
    }

    static class DummyTabFactory implements TabContentFactory {
        private final Context mContext;

        public DummyTabFactory(Context context) {
            mContext = context;
        }

        @Override
        public View createTabContent(String tag) {
            View v = new View(mContext);
            v.setMinimumWidth(0);
            v.setMinimumHeight(0);
            return v;
        }
    }

    static class SavedState extends BaseSavedState {
        String curTab;

        SavedState(Parcelable superState) {
            super(superState);
        }

        private SavedState(Parcel in) {
            super(in);
            curTab = in.readString();
        }

        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
            out.writeString(curTab);
        }

        @Override
        public String toString() {
            return "FragmentTabHost.SavedState{"
                    + Integer.toHexString(System.identityHashCode(this))
                    + " curTab=" + curTab + "}";
        }

        public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }

    public MyFragmentTabHost(Context context) {
        // Note that we call through to the version that takes an AttributeSet,
        // because the simple Context construct can result in a broken object!
        super(context, null);
        initFragmentTabHost(context, null);
    }

    public MyFragmentTabHost(Context context, AttributeSet attrs) {
        super(context, attrs);
        initFragmentTabHost(context, attrs);
    }

    private void initFragmentTabHost(Context context, AttributeSet attrs) {
        TypedArray a = context.obtainStyledAttributes(attrs,
                new int[] { android.R.attr.inflatedId }, 0, 0);
        mContainerId = a.getResourceId(0, 0);
        a.recycle();

        super.setOnTabChangedListener(this);
    }

    private void ensureHierarchy(Context context) {
        // If owner hasn't made its own view hierarchy, then as a convenience
        // we will construct a standard one here.
        if (findViewById(android.R.id.tabs) == null) {
            LinearLayout ll = new LinearLayout(context);
            ll.setOrientation(LinearLayout.VERTICAL);
            addView(ll, new LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.MATCH_PARENT));

            TabWidget tw = new TabWidget(context);
            tw.setId(android.R.id.tabs);
            tw.setOrientation(TabWidget.HORIZONTAL);
            ll.addView(tw, new LinearLayout.LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT, 0));

            FrameLayout fl = new FrameLayout(context);
            fl.setId(android.R.id.tabcontent);
            ll.addView(fl, new LinearLayout.LayoutParams(0, 0, 0));

            mRealTabContent = fl = new FrameLayout(context);
            mRealTabContent.setId(mContainerId);
            ll.addView(fl, new LinearLayout.LayoutParams(
                    LinearLayout.LayoutParams.MATCH_PARENT, 0, 1));
        }
    }

    /**
     * @deprecated Don't call the original TabHost setup, you must instead call
     *             {@link #setup(Context, FragmentManager)} or
     *             {@link #setup(Context, FragmentManager, int)}.
     */
    @Override
    @Deprecated
    public void setup() {
        throw new IllegalStateException(
                "Must call setup() that takes a Context and FragmentManager");
    }

    public void setup(Context context, FragmentManager manager) {
        ensureHierarchy(context); // Ensure views required by super.setup()
        super.setup();
        mContext = context;
        mFragmentManager = manager;
        ensureContent();
    }

    public void setup(Context context, FragmentManager manager, int containerId) {
        ensureHierarchy(context); // Ensure views required by super.setup()
        super.setup();
        mContext = context;
        mFragmentManager = manager;
        mContainerId = containerId;
        ensureContent();
        mRealTabContent.setId(containerId);

        // We must have an ID to be able to save/restore our state. If
        // the owner hasn't set one at this point, we will set it ourself.
        if (getId() == View.NO_ID) {
            setId(android.R.id.tabhost);
        }
    }

    private void ensureContent() {
        if (mRealTabContent == null) {
            mRealTabContent = (FrameLayout) findViewById(mContainerId);
            if (mRealTabContent == null) {
                throw new IllegalStateException(
                        "No tab content FrameLayout found for id "
                                + mContainerId);
            }
        }
    }

    @Override
    public void setOnTabChangedListener(OnTabChangeListener l) {
        mOnTabChangeListener = l;
    }

    public void addTab(TabSpec tabSpec, Class<?> clss, Bundle args) {
        tabSpec.setContent(new DummyTabFactory(mContext));  
        String tag = tabSpec.getTag();
  
        TabInfo info = new TabInfo(tag, clss, args);  
  
        if (mAttached) {  
            // If we are already attached to the window, then check to make  
            // sure this tab's fragment is inactive if it exists. This shouldn't  
            // normally happen.  
            info.fragment = mFragmentManager.findFragmentByTag(tag);  
            if (info.fragment != null && !info.fragment.isDetached()) {  
                FragmentTransaction ft = mFragmentManager.beginTransaction();  
//              ft.detach(info.fragment);  
                ft.hide(info.fragment);  
                ft.commitAllowingStateLoss();
            }  
        }  
  
        mTabs.add(info);  
        addTab(tabSpec);  
    }  
  
    @Override
    protected void onAttachedToWindow() {  
        super.onAttachedToWindow();  
  
        String currentTab = getCurrentTabTag();
  
        // Go through all tabs and make sure their fragments match  
        // the correct state.  
        FragmentTransaction ft = null;  
        for (int i = 0; i < mTabs.size(); i++) {  
            TabInfo tab = mTabs.get(i);  
            tab.fragment = mFragmentManager.findFragmentByTag(tab.tag);  
//          if (tab.fragment != null && !tab.fragment.isDetached()) {  
            if (tab.fragment != null) {  
                if (tab.tag.equals(currentTab)) {  
                    // The fragment for this tab is already there and  
                    // active, and it is what we really want to have  
                    // as the current tab. Nothing to do.  
                    mLastTab = tab;  
                } else {  
                    // This fragment was restored in the active state,  
                    // but is not the current tab. Deactivate it.  
                    if (ft == null) {  
                        ft = mFragmentManager.beginTransaction();  
                    }  
//                  ft.detach(tab.fragment);  
                    ft.hide(tab.fragment);  
                }  
            }  
        }  
  
        // We are now ready to go. Make sure we are switched to the  
        // correct tab.  
        mAttached = true;  
        ft = doTabChanged(currentTab, ft);  
        if (ft != null) {  
            ft.commitAllowingStateLoss();
            mFragmentManager.executePendingTransactions();  
        }  
    }  
  
    @Override
    protected void onDetachedFromWindow() {  
        super.onDetachedFromWindow();  
        mAttached = false;  
    }  
  
    @Override
    protected Parcelable onSaveInstanceState() {
        Parcelable superState = super.onSaveInstanceState();
        SavedState ss = new SavedState(superState);  
        ss.curTab = getCurrentTabTag();  
        return ss;  
    }  
  
    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        SavedState ss = (SavedState) state;  
        super.onRestoreInstanceState(ss.getSuperState());  
        setCurrentTabByTag(ss.curTab);  
    }  
  
    @Override
    public void onTabChanged(String tabId) {
        if (mAttached) {  
            FragmentTransaction ft = doTabChanged(tabId, null);  
            if (ft != null) {  
                ft.commitAllowingStateLoss();
            }  
        }  
        if (mOnTabChangeListener != null) {  
            mOnTabChangeListener.onTabChanged(tabId);  
        }  
    }  
  
    private FragmentTransaction doTabChanged(String tabId,
            FragmentTransaction ft) {  
        TabInfo newTab = null;  
        for (int i = 0; i < mTabs.size(); i++) {  
            TabInfo tab = mTabs.get(i);  
            if (tab.tag.equals(tabId)) {  
                newTab = tab;  
            }  
        }  
        if (newTab == null) {  
            throw new IllegalStateException("No tab known for tag " + tabId);
        }  
        if (mLastTab != newTab) {  
            if (ft == null) {  
                ft = mFragmentManager.beginTransaction();  
            }  
            if (mLastTab != null) {  
                if (mLastTab.fragment != null) {  
                    //将detach替换为hide，隐藏Fragment  
//                  ft.detach(mLastTab.fragment);  
                    ft.hide(mLastTab.fragment);  
                }  
            }  
            if (newTab != null) {  
                if (newTab.fragment == null) {  
                    newTab.fragment = Fragment.instantiate(mContext,  
                            newTab.clss.getName(), newTab.args);  
                    ft.add(mContainerId, newTab.fragment, newTab.tag);  
                } else {  
                    //将attach替换为show，显示Fragment  
//                  ft.attach(newTab.fragment);  
                    ft.show(newTab.fragment);  
                }  
            }  
  
            mLastTab = newTab;  
        }  
        return ft;  
    }  
}  